Driving journal compound



Patented July 13, 1937 UNITED STATES PATENT OFFICE Standard Oil ration of Indiana No Drawing.

9 Claims.

This invention relates to a hard high melting point lubricant of the type used by railroads for driving journals. This socalled driving journal compound usually consists largely of a soda soap and a heavy viscous mineral oil. In some cases certain additional minor constituents may be present.

The object of my invention is to produce an improved lubricant of this type which will permit lower lubricant consumption, lower bearing temperature, etc. Detailed objects will become apparent as the description proceeds.

Driving journal compounds are applied in cast The lubricant and plate are pressed snugly against the axle by means of springs. The bearing pressures on the 20 journals are from 50 to 350. pounds per square inch of projected bearing area. The reversed thruston the journals and the end-play and jolt- A lubricant of this type must have proper structural characteristics so that it will feed uniformly through the plate to prevent the development of local hot spots and so that it will feed out fast enough to reduce the ill effects caused by high spots on the plate or journal; in other words it must take care of all but the most glaring mechanical deficiencies. On the other hand it must not feed too rapidly for three reasons: (1) high consumption makes for high labor costs in re- 4 filling cellars; (2) high consumption ultimately results in too thin a lubricant cake and the danger of a hot box; and (3). high consumption means high lubricant costs. The second impor- 45 tant requirement is that the driving journal compound should be of such a nature as to hold the journal to a minimum temperature rise when the locomotive is under full load and speed.

50 is highly important in this type of lubricant since they give the desired hard fibrous structure which is required. Calcium soaps, aluminum soaps, etc., are not satisfactory for use without sodium soaps. The proper selection of the fatty acid 55 portion of the soap molecule Company, Chicago,

Application Serial No. 10,7

as 35 to 40% is likewise of the Ill., a corpo- March 13, 1935,

highest importance and it is with this feature that the present invention is concerned.

It was formerly customary to make these soaps from various types of commercial fatty acids and in particular from commercial stearic acid" which was found to be more nearly satisfactory than other materials tried. However, the use of commercial stearic acid in the manufacture of soaps to be used in these driving journal compounds was by no means entirely satisfactory. If the soap content was kept fairly low the consumption of grease by the journal became inordinately high. On the other hand, when the soap content was raised to remedy this difficulty, much trouble was encountered from bearing failures, carbonization, etc.

It was found that a superior driving journal compound could be made by the use of certain hydrogenated fatty acids made from sources of unsaturated fatty acids containing largely acids of 18 or morecarbon These hydrogenated fatty acids contained a large portion of the chemical individual known as stearic acid. Thus, a typical hydrogenated fatty acidof this type may contain over 70% of stearic acid, from 7 to 8% of acids having 20 or 22 carbon atoms per molecule, about 10% of palmitic acid (16 carbon atoms per molecule) and from 12 to 15% of unsaturated acids. Driving journal compounds made from hydrogenated fatty acids of this type were found to be'highly superior to those made from commercial stearic acid,

A commercial stearic acid may contain as much as 40 to 60% of palmitic acidand as little of true stearic acid. The palmitic acid in commercial stearic acid is not removed by repeated pressings or by the other conventional methods of refining. Thus double or triple pressed stearic acid is usually thought to be highly pure and is in fact practically free from oleic acid and other low melting point material but still contains very large quantities of palmitic acid. The ratio of palmitic acid to .true stearic acid is not materially reduced by the repeated pressing since the palmitic acid and stearic acid tend to form a mixture. which is probably an eutectic.

The ratio of palmitic acid to stearic acid in commercial stearic acid is approximately constant for commercial stearic acid from all known natural sources.

The presence of palmitic acid in commercial stearic acid was thought to be the reason for its inferiority over the hydrogenated fatty acids since the latter differ from commercial stearic acid atoms to the molecule.

largely in their much lower palmitic acid content. I have discovered, however, that palmitic acid is by no means objectionable per se but is objectionable only in its admixture with large proportions of stearic acid.

Thus, either stearic acid relatively free from palmitic acid (i. e. hydrogenatedfatty acid) or palmitic acid relatively free from stearic acid, is far superior to the niixture known commercially as stearic acid. I find, moreover, that the relatively pure palmitic acid is not only highly superior to the commercial stearic acid" but is also definitely superior to the hydrogenated fatty acids for the manufacture of driving journal compounds.

This superiority of driving journal compounds made from soda soaps of palmitic acid includes both of the important considerations mentioned in the introductory paragraphs of this specification. In other words, the consumption of driving journal compound by the bearing under given test conditions is lower and the temperature rise in the bearing is also lower for a given soap content. A bearing using a driving journal compound containing a palmitic acid soap will run cooler and at the same time consume less lubricant than a bearing running under identical conditions using a driving journal compound containing soap made either from commercial stearic acid or from the relatively pure stearic acid known as hydrogenated fatty acids. Thus, in a bearing test using driving journal compounds containing 48.5% of various soaps and being otherwise identical, the bearing consumed 10 grams of a compound containing soap made from Bakers technical palmitic acid, while under identical conditions and during the identical period it consumed 15 grams of a compound made from sodium soaps of hydrogenated fatty acids. A compound made from a :50 mixture of the soaps of the two preceding examples gave a consumption of 80 grams. The corresponding consumption for a compound made from a sodium soap of commercial stearic aci is about 60 45 grams.

Other compositions were also made from a commercial mixture containing about 75% palmitic acid and 25% oleic acid and these compositions were tested in a standard bearing under standard ized load, speed and time cbnditions to determine bearing temperatures. The average maximum temperature to which the bearing rose during the test was noted. When the temperature rose to 325 the journal was stopped, the bearing was permitted to cool to 260 F. and the test was then continued. The following table shows results under identical conditions for a series of driving journal compounds using soaps of hydrogenated fatty acids on the one hand and of a relatively pure palmitic acid on the other hand, the compounds being otherwise identical.

Maximum bearing temperature It is apparent from this table that compounds made from palmitic acids give lower bearing temperatures for a given soap content. In the case of the highest soap contents this is apparent from the increased number of stops during the fixed test period necessary to cool the bearing when using a compound made from the soaps of hydrogenated fatty acids.

Driving journal compounds in accordance with my invention may vary considerably in composition. The soap content is the most important factor and this may vary from 30 to 55%. I prefer, however, to confine the range to approximately 35 to 45%. Both the consumption of the lubricant by the bearing and the temperature to which the bearing rises are increased as the soap content of the lubricant is increased and it is therefore desirable to avoid using too much soap. The consumption curve appears to take a sharp rise at about 42% soap and I therefore prefer to keep under this figure. The 42% figure is subject to variation either up or down with slight variations in the nature of the soap stock and with other variables. The soap content must not be too low or the driving joumal' compound loses its desired hard fibrous structure and becomes too soft. Furthermore, if the soap content is progressively lowered a point is reached at which the consumption begins to rise as it does in the case of too high a soap content.

I may also use a small amount of pure fat or however, be entirely eliminated, but when this is done it is desirable to increase the soap content by 1 or 2%. My driving journal compounds will also usually contain a very small amount of water which tends to give the desired fibrous structure. The water content should, however, be less than 1% and usually less than 0.1%. The remainder of my compound is made up of oil. Any kind of heavy viscous lubricating oil is suitable but I find it best to use some type of residual oil, such as steam-refined oil. I also find it advantageous to include a small amount of a heavy black oil such as-is' produced from Wyoming crudes; This may be present in quantities oi. from 1 to 50% of the total oil but preferably from about 5 to 20% of the total oil. Various other materials, for instance fillers, such as graphite, asbestos, mica, etc., can be used and if used they are in addition to the constituents already mentioned and are not to be considered in calculating the amounts of the main constituents. The use of such materials is not recommended in ordinary cases.

A typical example of a composition according to my invention is as follows:

Driving journal compounds in accordance with my invention can be made by various methods. In a preferred method the fatty acid is melted in the heavy mineral oil at 220-325 F. in a steam kettle equipped with a mixer. Sodium hydroxide is then added thereto in the form of an aqueous solution, for example 48% strength, with constant stirring until complete neutralization has been effected and the batch has become heavy and Percent Sodium palmitate (technical grade) 40 No. 1 lard oil 2.5 I

Heavy black oil 8 Steam refined oil (530 F. flash) 49.5

Total beng equivalent to about .02 to +.02% sodium hydroxide. The lard oil is next added and worked in with stirring at a temperature below the are usually very unsatisfactory. This appears to be due in part to the fact that glycerine is an undesirable constituent in my compounds although a compound made from fatty acids and containing the stoichiometrically equivalent amount of glycerine is superior to an otherwise similar grease made from fats.

The palmitic acids used in making my compounds may come from any desired natural source. One good source is fatty acids from palm which can be separated by efiicient fractional distillation, preferably under vacuum, to produce a fraction containing a high concentration of the chemical compound palmitic acid.

I strongly prefer to use soaps containing at least 65% and preferably at least 70% of the chemical compound sodium palmitate. Progressively higher contents of sodium palmitate, e. g. 80%, 90% and 95%, are increasingly desirable. Another important factor is to keep the sodium stearate content down since sodium oleate and other soaps appear to be far less detrimentalthan sodium stearate. It is highly important that the content of the latter be kept under 15% and preferably under The percentages given in this specification are expressed in terms of weight.

It can generally be said that driving journal compounds in accordance with my invention contain shorter and thinner fibers than those of the prior art.

While I have described my invention in connection with certain specific embodiments and in connection with certain theories, it is to be understood that these are by way of illustration only and not by way of limitation.

I claim:

l. A hard high melting point driving journal compound consisting largely of soda soap and a heavy viscous mineral oil, each present in large proportion, said soda soap containing at least about.70% sodium palmitate.

2. A hard high melting point driving journal compound consisting largely of soda soap and a heavy viscous mineral oil, each present in large Percent Soda soap 30-55 Heavy viscous mineral oil 34-70 Free fat and fatty acid 0-10 Water 0-1 said soda soap containing at least about 70% sodium palmitate.

5. A substantially glycerine free driving journal compound comprising the following constituents in substantiallythe following percentages by weight:

. Percent Soda soap 30-55 Heavy viscous mineral oil 34-70 Free fat and fatty acid 0-10 Water 0-1 said soda soap,containing at least about 65% sodium palmitate and not more than about sodium stearate.

6. A driving journal compound comprising the following constituents in substantially the fol- ;lowing percentages by weight:

Percent soda soap, 35-45 Heavy viscous mineral oil 48-62 Free fat and fatty acid 33-! Water 0-0.1

said soda soap containing at least about 70% sodium palmitate.

7. A driving journal compound comprising the following constituents in substantially the following percentages by weight:

Percent Soda soap 35-45 Heavy viscous mineral oil 48-62 said soda soap containing at least about 70% sodium palmitate.

8. A substantially glycerine free driving journal compound comprising the following constituents in substantially the following percentages by weight:

Percent Soda soap 35-45 Heavy viscous mineral oil 48-62 said soda soap containing at least about 70% sodium palmitate and not more than about 10% sodium stearate.

9. A driving journal compound having substantially the following weight composition:

. Percent Soda soap 40 Steam refined oil 49 Heavy black oil 8 Lard oil 2.5 Water 0-0.1

said soda soap containing at leastabout 65% sodium palmitate and not more than about 15% sodium stearate.

wmmm'r. mm.

CERTIFICATE OF CORRECTION.

Patent No. 2,086,870. July 15', 1957.

WILLIAM P. HILLIKER.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 5, second column, line 6'7, claim 9, in the table, for the numeral "4-9" read 49.5; and that the said Letters Patent should be read with this correction therein that the Same may conform to the record of the case in the Patent Signed and sealed this 21st day of September, A. D. 1937.

Henry Van Arsdale (Seal) Acting Commissioner of Patents. 

